The Royals' Opening Day roster doesn't have to be finalized for another 16 days but indications are that those three pitchers will join Wade Davis, Louis Coleman and closer Greg Holland in six of the seven relief spots.

Any question marks?

"Pretty much just for the seventh guy," manager Ned Yost said on Friday.

"I thought Crow, Collins and Herrera needed to make adjustments coming into camp and I think all three of them have done a great job with it," Yost said. "I'm very pleased with what I see out of those three.

"I'm happy that we have a force like Wade Davis in the 'pen. I think that Holly is Holly, I'm happy to have him, one of the best closers in the American League. Louis is doing fine. Louis is a proven performer that got set back a little bit with his [jammed] finger but I think he's on track to be OK."

The Royals still are pondering the wisdom of sending either Duffy or Ventura down to Triple-A Omaha to start regularly in the Storm Chasers' rotation just in case a Kansas City starter is injured or falters. The other option is sliding one of them into the bullpen.

"If something happens, you've got to have a guy you can count on to step up and pitch in the starting rotation," Yost said. "But you also want to get off to a good start. You want to take your 12 best pitchers. So we're still thinking through that; we've still got 13 days left to do that."

The Royals break camp on March 27 and head to Milwaukee for their last two Spring Training games.

Previously Yost said he was 50-50 on whether to keep a "long man" in the bullpen.

"OK, you guys are good. I thought maybe I'd stump you with that one," he said.

What about those adjustments that Crow, Collins and Herrera needed to make?

"Consistency is key," Yost said. "You've got to be able to come in and throw strikes. You have to, and all three of them have worked real hard on their feel and touch, they're staying within themselves and refining their mechanics so they're consistent."

Throwing effective strikes often comes with not trying to fire flames with every pitch. Collins learned by watching Holland and Bruce Chen over the last few years.

"It finally hit me, I don't have to throw 100 [mph] to get guys out," Collins said. "I watch Greg do it throwing 98 and I watch Bruce doing it throwing 82. So I don't really see much difference there as far as their results."

The ability to dominate comes with pitch location too.

"The hitters can hit a 100-mph fastball if you leave it up," Herrera said. "But it's harder to hit it down and away or in the lower part of the strike zone. So I think the most important thing is keep the ball down. That way you can get a ground ball or even a swing and a miss."

And, of course, keeping cool in the heat of a situation is essential for a reliever.

"If you're pitching in Yankee Stadium," Crow said, "you can't let the atmosphere and the crowd affect you even though sometimes it can help -- an adrenaline rush can make you better sometimes -- but the best thing for any pitcher is to stay calm and collected on the mound."

Crow, Herrera and Collins have learned their lessons and passed the Yost test.

"Our bullpen is as good as any bullpen in baseball, especially in the American League, and you can ask any team that," Yost said. "But I have to know what I'm getting every day. I can't bring a guy in hoping that he's going to throw strikes or wondering if he's going to throw strikes."

The manager knows he's going to get firepower -- "Everybody throws gas," he said -- even if it's dialed back occasionally for location or deception, and there's another element that Yost is certain he'll get from his relievers.

"What makes them so special for me -- and it's been like this now for two years -- none of them are scared," Yost said. "I've never had a 'pen where you didn't have two or three guys that weren't a little shaky when you bring 'em in. These guys -- there's not a soul out there where you see any type of uncertainty when you bring them in the game."

Something else Yost sees in his bullpen is flexibility -- Holland is his closer but everyone else can fit in anywhere -- set up, middle innings or long.

"I can mix and match any of them," Yost said. "I'm not going to have one eighth-inning guy. The only guy that's going to pitch the ninth inning is Holly, unless he's pitched four days in a row. I can use anybody else in any other situation and feel like we're going to get the job done. That's why they're so good, they complement each other."

Naturally, there'll be bumpy times along with the smooth but Herrera has an answer for that, too.

"Try to keep the bad days to a minimum," he said.

Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.